Commutator.



F. G. FISCHER.

00111111111103. 7 APPLICATION FILED SEPT. 8, 1910.

984,655- Patented Feb. 21, 1911.

FIG. Z- 2 FIZZ] Q M a A V 41m I 411* FIG 5 F181 6'. FIG. 7.

I a, w a, m 61 A TTORNE Y ing a citizen of the copper 0 v ry unsatisfactory,

, again begins beneath the 'ortion of the comnately arranged 4\5 tions or parts" thereof, and also illustrative UNITED STATES PATENT OFFICE.

FBIEDRiCH c. rrscnnn, or rmnnnnmnia, PENNSYLVANIA.

conmu'rmoa.

Specification of Itetters Patent.

Patented Feb. '21, 1911.

Application filed September a, 1910. Serial No'. 581,040.

10. which. the following is aspecification.

A commutator is generally arranged with bars and mica sections disposed longitudinally side by side about the axis of the same. The mica commonly used bein lstermed micanite which consists of smal pieces of mica held together by shellac or varnish. In service, as often happens bits of copper, carbon or particles of oil will deposit on the micanite as well as in small cracks or crevices formed in the same, thus furnishing a good conducting path to the copper bars of the commutator and hence for the current to leak from one cop er bar to the other thereof, resulting finally in what is called pitting The almost universal practice, in order to provide for pitting is to scrape out the formed cracks or crevices and fill with French chalk, powdered mica, silicate of soda or the like but this has been because soon leakage mutator acked with suc material.

The principal object of my invention is to in case of pitting provide a simple, practical, effective and inexpensive manner of providing for pitting. I

The natureand sco e of my present invention will be more ully understood from the following description taken in connection with the accompanying drawings forming art-hereof,-in which- 4 Flgure 1, is a perspective viewof the sections of a commutator, showing the altermetal and micanite 'secof the irregular pitting of the micanite sections of the same taking place in the service thereof. Fig. 2, is a transverse sectional view through a commutator, showlng' the assembled copper and mica or micanlte sections or parts oft-he commutator and in end elevation an"instrument. of a preferred arrangement for forming required shaped re-' cesses in defective parts or sections of the commutator to receive such repair inserts.

onto the readily shi Figs. 3 and 4, are'perspective views respectively, of sections of a commutator with their variableshaped recesses to receive correspondin repair inserts of mica or micanite; and igs. 5, 6 and 7, are respectively, in

elevation several different forms of recesses that are provided to recelve repair insert parts, so as to quickly remedy pitting of the insulating sections or parts of a commutator.

In the drawings, A represents a commutator composed of two series of Qiblong sections or parts a and a", of copper and mica,

micanite or other similar insulating mate r al, in operative relation arranged side by side, throughout the structure as shown in Fig. 2.

b and 6 are two circular saws of differing diameters and each provided with teeth around the peripheries of the same. The radius of thelargest of the saws clamped together is about half an' inch less than the radial depth of the insulation of the micanite or ot er material separating the copper commutator bars. In this way the repair operation can be effected without danger of cutting entirely through the commutator.

The saws as shown, are mounted on a shaft b, with which operating means, not shown,

may be connected for revolving the same.

The Rclam ed. saws'to operate are lowered efective section and rotated. and shifted :during cutting into the mica or micanite deep enough to entirely remove defective material so that the repair part. or

piece to be. inserted will correspond substan tially to the recess made by the saws, When the-repair insert or part has been inserted intotlie' recess it iscemented therein. If-

after insertion 'it, is found pittin' has extended to a' greater extent of the mica or -micanite part or section of the commutator than was su posed, the clamped saws can be ed to e'ifect a cut substantially coextensive with-that of the impaired structure toreceive a repair insertor part, 210- cordin to my invention and so as also to be r-ea, 1y secured i'nplace therein. Y I

' Having thus I v jects of my invention, what I claim as-new.

and desire to secure by Letters Patent is:-

The herein described mode of repairing commutators, which consists in. mechanicall forming anyin'cision of variable shape or orm in a defective part or section of a described the nature and obcommutator at one time and applying an inmy signature in the presence of two subsertpzziilt or section sha e or form corscribing witnesses. res on 'ng to t at o the Incision and se cur in in position, to again establish elec- FRIEDRICH FISCHER 5 trical y normal relations or conditions of Witnesses:

the commutator. r JOHN J. KELLY,

In witness whereof, I have hereunto set MARY AGNES KELLY. 

